1. Field of Invention
This invention relates to improvements in methods and apparatus for producing biochips, such as biomolecules, such as DNA, RNA, protein and sugar chain molecules, which are arranged in arrays on a substrate.
2. Description of the Prior Art
The prior art can be understood by taking DNA chips as an example. Generally, DNA chips are 1 to 10 cm2 in size and several thousand to several hundred thousand types of DNA segments are arranged within the area of such chips. One conventional method of producing the biochips comprises the steps of stamping and depositing a solution of DNA segments prepared by a polymerase chain reaction (henceforth referred herein as “PCR”) onto a slide glass or silicon substrate using pins on an arrayer, or by synthesizing a large quantity of DNA segments at one time on a glass substrate using semiconductor techniques.
FIG. 1 shows conventional method, wherein the tip of pin 1 is first dipped in a washing fluid contained in chamber 2, for cleaning the pin tip. Next, pin 1 is moved to a solution chamber 3 and dipped thereinto so that DNA segments are caused to adhere to the tip of pin 1. Finally, pin 1 is moved and pressed on a slide glass 4 to produce a DNA chip.
The prior art methods are plagued with problems, such as, for example:
(1) The process of deposition of the DNA segments using a pin consumes a long length of time, and the quality of a stamped site (referred to hereinafter as “cell” or “spot” or “site”) is not uniform. Moreover, it is difficult to deposit only a small amount of DNA solution. Thus, waste becomes a factor.
(2) The method of synthesizing a large quantity of DNA segments at one time on a glass substrate by using semiconductor techniques requires large scale factory equipment. Thus, cost becomes a large factor.